We address the problem of designing distributed Multiple Access Control algorithms for wireless networks under the SINR interference model. In the proposed framework, time is divided into frames consisting of a fixed number of slots, and transmitters may adapt the power levels used in the various slots. We aim at developing fully distributed multiple access algorithms that are throughput-optimal in the sense that they perform as well as centralized scheduling algorithms. These algorithms based on a simple power control mechanism, referred to as Power Packing. This mechanism allows each transmitter to tune their power levels in the different slots so as to achieve a target rate while minimizing the number of slots actually used. The proposed algorithms are throughput-optimal, simple and do not require any message passing: each transmitter adapts its power levels depending on the observed interference levels in the various slots. We illustrate the efficiency of our algorithms using numerical experiments.